At the same time, it’s important to understand that the relational model is independent of (and prior to) SQL. SQL is by far the most commonly used language implementation and is important because of that, but it also deviates from the relational model in subtle (and sometimes not so subtle) ways. Understanding those differences and how to accommodate for them can be important to understanding how to write schema and queries in more holistic and powerful ways.
And to be fair, I wouldn’t have found the relational model without SQL. I wish it were more common to write about both in SQL tutorials and such, but I understand the motivation to write about what people can do with an implementation rather than the mathematical and logical underpinnings.
